Army bomb experts have dealt with four devices during a major investigation into dissident republican terrorism in the Republic of Ireland.
Specialists made safe devices found in counties Wexford, Leitrim and Louth.
Several police teams also carried out a total of 20 searches in counties Louth, Dublin and Wexford.
The Irish justice minister Frances Fitzgerald said the country was prepared for any security threat posed by terrorists.
A major cross-border security operation is expected to be put in place over the weekend ahead of the first official joint visit to Ireland by Prince Charles and his wife Camilla, the Duchess of Cornwall.
"I expect Prince Charles will have a very positive visit here, and clearly the gardaí [police] are alert to any security issues and will deal with any security issues that are arising," Ms Fitzgerald said.
Six men were arrested after the seizure of pipe bombs, bomb components, a firearm and ammunition.
A controlled explosion was carried out in Dromiskin, County Louth.
The Irish Defence Forces said component parts were made safe at the scene and the explosive material was destroyed.
A team of bomb experts made safe two viable improvised explosive devices in the Manorhamilton area of County Leitrim.
A suspect device was found during a vehicle search by police and a cordon was put in place for public safety.
A bomb disposal team made safe component parts of explosive device-making equipment in Courtown, County Wexford.
The parts were found during a search of a private residence in Courtown by police on Wednesday evening.
A small number of nearby houses were evacuated for a time.
Meanwhile, in a separate development police stopped a car in County Leitrim on the road to Blacklion in Cavan and found a pistol and two pipe bombs.